1. Field of The Invention
This invention relates to an electronic musical instrument, and more particularly, to a tone pitch (hereunder referred to simply as a pitch) changing device for use in electronic musical instruments.
2. Description of the Related Art
Conventionally, an electronic musical instrument in which a temperament, such as an equal temperament can be selected from various tunes is provided with a pitch changing device having a memory which stores an operation expression for calculating data used to obtain desired pitches in the selected tune, or with an operational decoder for executing the operation expression. Namely, each time a pitch is indicated, the pitch changing device calculates the data corresponding to the indicated pitch, on the basis of the stored operation expression or a decoding program to be effected in the operational decoder, and outputs the thus calculated data.
Alternatively, there is known a conventional pitch changing device provided with a memory which stores precalculated data corresponding to all pitches to be selected or indicated, reads data therefrom corresponding to the indicated pitch and outputs the thus read-out data.
In the former conventional pitch changing device, however, which calculates data each time a pitch is indicated, a relatively long time is needed for the calculation and output of the data, and thus this device has a disadvantageous slow responsitivity.
The latter conventional pitch changing device, which precalculates and stores data of all of the pitches for each temperament, has a drawback in that it requires a very large memory capacity.
The present invention has been created in order to eliminate the above describe drawbacks of the conventional pitch changing devices.